Glass tube forming



April .12, 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27. 1960 7 Sheets-Sheet 1 INVENTORJ N IVORMHN fife/e590 N K1 02 AND (706w 14-dE/FERT (D m I 41MB. TM

AGENT April 12, 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27, 1960 7 Sheets-Sheet 2 INVENTOR Noe/MN Nola/5nd 4ND Jan/v r4- JE/FE E MM 1:. M

146' E N T April .12, 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27, 1960 7 Sheets-Sheet :5

INVENTORS /V0/P/ m/v MO/QEAU 's on/v 4. Sen-"5R7 41MB. 579M AGENT p 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27, 1960 7 Sheets-Sheet 4 AGENT April 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27, 1960 7 Sheets-Sheet 5 -t-6 MM AAMA April 12, 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27, 1960 Sheets-Sheet 6 l7 AGENT April 1966 N. MOREAU ETAL 3,245,773

GLASS TUBE FORMING Original Filed Oct. 27, 1960 7 Sheets-Sheet 7 NUMBER OF NOLDS I \J N M137 M135 2 No.37

MOLD CAM/IV LENGTH A/MDM Eur United States Patent 3,245,773 GLASS TUBE FORMING Norman Moreau, Lincoln, and John A. Seifert, Cranston, R.I., assignors to Corning Glass Works, Corning, N.Y., a corporation of New York Original application Oct. 27, 1960, Ser. No. 65,339, now Patent No. 3,181,941, dated May 4, 1965. Divided and this application Oct. 29, 1964, Ser. No. 414,047 2 Claims. (Cl. 65-187) This application is a division of our copending application Serial No. 65,339, filed on October 27, 1960, now Patent 3,181,941.

The present invention relates to a method of and apparatus for modifying the form of glass tubing while traveling from a source of formation toward a delivery position.

It has been discovered that tubular electric lamps, of greatly increased efliciency, can be obtained by imparting to their envelopes a configuration in which the perimeterto-area ratio is greater than that of round tubes of like cross sectional area, and that such tubes have greater strength and higher resistance to implosion than simple flattened tubes. Preferred forms of such a tubular electric lamp are fully shown and described in United States Patent No. 2,915,664. A presently known method of and apparatus, respectively, for reforming individual glass tubes in the production of such lamps are disclosed in United States Patent Nos. 2,862,337 and 2,862,335.

According to the invention a tubular stream of molten glass issuing from a tube making forehearth and traveling toward a delivery position is, near its source, encircled with embracing members or cylindrical molds having passages through the walls thereof. Cams along the common path of travel of the stream and molds project tools through such passages to modify the form of the tubing in a desired manner. Before the path of travel of the molds divert from that of the tubular glass stream such tools are withdrawn and such molds separated to permit the tube to continue uninterruptedly on its course. In the meantime the molds return to position for subsequent embracement of the oncoming tubing.

For a full understanding of the invention reference is made to the accompanying drawings.

In the drawings, FIGS. 1 and 1a together comprise a plan view, partly in section, of a machine embodying the invention.

FIG. 2 is a view of a fragment of the machine, partly in section, as seen when looking in the direction indicated by arrows 22 in FIG. 1.

FIG. 3 is a view of the machine as seen when looking in the direction indicated in FIG. 1 by arrows 3-3.

FIG. 4 is a top plan view, on an enlarged scale and partly in section, of the chain of molds and of sprocket wheels about which the chains are trained.

FIG. 5 is a side elevational view of part of one of the chains with some of the molds shown and with mold halves completing an end turn about one of the sprocket wheels.

FIG. 6 is a sectional view taken on line 66 of FIG. 5.

FIGS. 7 and 8 are similar cross sectional views of other forms of molds employed.

FIG. 9 is a diagrammatic view showing the machine in association with a horizontal tube drawing forehearth and a tube drawing tractor.

FIG. 10 is a straight line diagram illustrating the combination of chain supported molds in the machine as illustrated.

As will be observed from FIGS. 1, 1a and FIG. 3, a carriage 16 has arranged thereon endless chains 17 and 18 trained about drive sprocket wheels 21 and 22 and about idler sprocket wheels 24 and 25 respectively. Sprocket wheels 21 and 22 are suitably keyed to a shaft 23 driven by a motor 26 through the medium of a belt 29, a speed regulating unit 30, a belt 31, a speed reducing unit 32 and a bearing 33.

The chains 17 and 18, which between their sprocket wheels ride on rails such as 46 (FIGS. 1 and 3), carry the respective halves of axially split molds such as molds 35, 36 and 37, best illustrated in FIGS. 6, 7 and 8, respectively. As will be seen from FIGS. 4 and 5 the mold halves on the one side of their center line are axially shifted with respect to their mating halves on the other side. This is done owing to the staggered arrangement of the indentations to be made in opposite sides of the tubing. These molds comprise mold halves such as 38 and 39 (FIG. 7) each having a bracket such as 41 or 43 pivoted about a pin such as 40 passing through a chain supported mold mounting bracket such as 49 or 50 and each mold half having a roller such as 42. Springs such as 44 or 45 bias the mold halves to their open positions as shown in FIG. 2. To close the mold halves about the tubing as their path of travel joins that of the tubing there are provided cam tracks 47 and 48 (FIGS. 2 and 3) engageable by their rollers such as 42.

Cam tracks 47 and 48 are mounted on suitable upright guide posts 51 and 52 respectively and are held in properly adjusted positions by locking screws such as 53. To facilitate adjustment of cam tracks 47 and 48, they are provided with slots into which bell cranks such as 55 are projected. These bell cranks are pivoted as at 57 and are turned about their pivots by means of adjusting screws such as 63. When the proper positions of the cam tracks have ben established the screws such as 53 are tightened.

Blank molds such as 37 (FIG. 8) serve as spacers and simply embrace the tubing along lengths thereof wherein no reforming of the tubing is to be effected, there being a number of these molds determined by the length of plain tubing it is desired to have between the respective reformed sections thereof.

Adjoining each end of a row of molds such as 37 is a mold 36, as shown in FIG. 7. Such a mold is provided with plungers 65 and 66 for reforming the tubing in a manner to form mercury pockets therein as required at each end of a fluorescent tube.

Each plunger such as 65 or 66 is locked against turning about the axis of its supporting slide rod such as 68 by a key such as 69 pressed into a groove in such rod and slidable in a groove such as 70 (FIG. 8) in a bracket such as 73 attached to the mold half and occupied by rod 68. In and out movement of a plunger is accomplished by means of an actuator pin 71 passing through a slot in bracket such as 73 and threaded into rod 68. Pin 71 is straddled by the end of an actuator arm such as 72 as best shown in FIG. 4. The arms such as 72 are pivoted as at 75 and carry operating rollers such as the roller 76. As best illustrated in FIGS. 1 and 2 cam tracks 81 and 82 are arranged for engagement of the rollers such as 76 while a mold embraces the tubing. Cam tracks 81 and 82 are mounted on suitable transverse slide ways such as 85 and are laterally adjustable by means of screws such as 87. The molds such as 35 (FIG. 6) are identical to those such as 36 except for the difference in their plunger shape.

Before .a mold arrives at the end of its travel with the tubing the rollers such as 76 travel off the end of the cam tracks 81 and 82 and encounter plunger pull out cams 88 (FIG. 1) and 89, mounted on brackets 93 and 94, respectively, and which withdraw the plungers from association with the tubing before the mold arrives at the region of sprocket wheels 21 and 22 and start to be separated from one another under the influence of springs 3 such as 44 and 45 as the rollers such as 42 become disengaged from cam tracks 47 and 48.

Referring now to FIG. 9 a forehearth 90 has been shown having a tubular stream 91 of glass issuing therefrom being horizontally drawn by a tractor 92, but which may be dispensed with while employing applicants forming machine. As the tubing passes through such machine the respective molds close thereabout and the tubing is formed with pockets while embraced with molds such as 35 and 36 in a manner clear from the preceding description.

Referring now to FIG. 10, it will be seen that in the particular embodiment of the invention illustrated, there is a series of nineteen molds such as 35 flanged on either side by a mold 36, with the space between molds 36 separated by ten blank molds 37. There will accordingly be one section of tubing formed for each complete cycle of travel of the chains 17 and 18.

Although the invention is illustrated as applied to horizontal drawing of tubing, it obviously is not limited to such use, since if desired, the machine may equally Well be mounted vertically and .fed with tubing either from an up-drawn or a down-draw source without departing from the. invention as described and hereinafter claimed. Moreover, although a tractor is illustrated as used as is common practice in drawing tubing, it will be appreciated that applicants machine is itself a tractor andmay be so employed in the drawing of tubing horizontally or vertically; and that when used with a down-draw system may even be employed in a manner to counteract the tendency of acceleration of rate of draw otherwise resulting from the weight of the pendant glass tubing issuing from such a system.

What is claimed is:

1. The combination with a glass Working apparatus which includes means for continuously issuing a hollow stream of molten glass from a parent supply body thereof, of an endless chain embodying a series of axially split molds, means providing a path of travel for the molds in part including the stream path, means for closing said molds about the stream as their path of travel joins that of the stream and for opening them before'their path of travel diverts from the stream path, tools for performing shaping operations on the stream accessible to the stream through transverse passages in said molds, and means for moving said tools through such passages into and out of the stream to modify its shape while said molds are closed about the stream.

2. Glass working apparatus which includes means for issuing a hollow stream of molten glass froma parent body, a mold embodying a cylindrical wall axially split and closeable about the stream, stream reshaping means means movable through. a passage in the mold wall to reshape the. portion of the stream within the mold, means for moving. said mold and said streamreshaping means along the, path of travel of said hollow stream, means for moving said stream reshaping means into and out of the portion of the stream surrounded by the mold and means for thereafter removing the mold from about the stream.

References Cited by the Examiner UNITED STATES PATENTS 1,678,104 7/1928 Cole -295 X 2,045,699 6/1936 Cramer 65184 X 2,166,871 7/1939 Luertzing 65-87 X 2,502,312 3/1950 Danner 65-184 DONALL H. SYLVESTER, Primary Examiner. 

1. THE COMBINATION WITH A GLASS WORKING APPARATUS WHICH INCLUDES MEANS FOR CONTINUOUSLY ISSUING A HOLLOW STREAM OF MOLTEN GLASS FROM A PARENT SUPPLY BODY THEREOF, OF AN ENDLESS CHAIN EMBODYING A SERIES OF AXIALLY SPLIT MOLDS, MEANS PROVIDING A PATH OF TRAVEL FOR THE MOLDS IN PART INCLUDING THE STREAM PATH, MEANS FOR CLOSING SAID MOLDS ABOUT THE STREAM AS THEIR PATH OF TRAVEL JOINS THAT OF THE STREAM AND FOR OPENING THEM BEFORE THEIR PATH OF TRAVEL DIVERTS FROM THE STREAM PATH, TOOLS FOR PERFORMING SHAPING OPERATIONS ON THE STREAM ACCESSIBLE TO THE STREAM THROUGH TRANSVERSE PASSAGES IN SAID MOLDS, AND MEANS FOR MOVING SAID TOOLS THROUGH SUCH PASSAGES INTO AND OUT OF THE STREAM TO MODIFY ITS SHAPE WHILE SAID MOLDS ARE CLOSED ABOUT THE STREAM. 